Electric warp stop motion for looms



Feb. 17, 1948. v. F. SEPAVICH ETAL ELECTRIC WARP STOP MOTION FOR LOOMS Filed May 10, 1945 INVENTORS Um 3.5% M BY WV) 0J6 Patented Feb. 17, 1948 nmc'rmc Wm s'ror MOTION FOR LOOMS Victor F. Sepavlch and John C. Manoog, Worcester, Msss., assignors to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application May 10, 1945, Serial No. 592,987

2 Claims. (01. 139-353) This invention relates to improvements in electric warp stop motions for looms and it is the general object of the invention to provide an electrical system which will be caused to operate by the flow of a very small current through the fallen drop wire.

Electric warp stop motions usually include one or more banks of drop wires through which are strung contact bars, Each bar is composed of two electrodes insulated from each other and so related-that when a drop wire falls due to breakage of the associated warp the electrodes will be electrically connected. As heretofore made the warp stop mechanism ha included a solenoid energized by a. relatively large electric current which passes through the fallen drop wire. This arrangement resulted in heating and burning of the drop wire.

It is an important object of our present invention to provide an electronic circuit which will be controlled by the drop wires and which will be operated by a very small current incapable of causing heating or burning of the drop wires.

A loom can ordinarily be stopped by. any one of several stopping mechanisms, such a the filling fork, protector, orwarp stop motion, and it is not always easy for the weaver to know just which fault of loom operation has caused the stoppage. In order that the warp stop motion can give a. signal when it is responsible for loom stoppage we use a lamp or other form of signal which will become energized whenever the Warp stop mechanism operates. The current for operating the lamp will ordinarily be larger than that which should pass through the drop wire, and in order to prevent the current which energizes the lamp from passing through the drop wire we connect the drop wire and lamp to the electronic circuit in such a Way that a very small current flowing through the drop wire will cause illumination of the lamp.

After the weaver has determined that loom stoppage has been caused by a warp fault he may have difiiculty in determining the location of the broken thread. In a type of electric warp stop motion heretofore developed and shown in Payne Patent No. 1,852,217 there is employed a form of drop wire having two ears or projections extending into the slot through which the contact liar extends, When the drop wire falls these projections engage the electrodes of the contact bar to connect them electrically. This form of drop wire can be made in such a shape as will facilitate the finding of the broken warp thread. There is an arch or cross bar at the top of the drop wire capable of engaging the upper part of the contact bar when the wire is tilted, after which further'tilting will disturb the contact between the electrodes and the drop wire sufllciently to cause a variation in any circuit established through a fallen drop wire. We utilize this type of drop wire in another feature of our invention and cause the variation in the drop wire contact to alter the potential of the grid of the electronic tube. Under ordinary conditions the grid is able to prevent firing of the tube, but when a drop wire falls the grid potential is changed and the tube can operate to energize an electromagnetic device such as a relay which controls the aforesaid lamp. Upon disturbance of the fallen drop wire the potential of the grid will be momentarily restored to normal in which case the lamp circuit will be interrupted to cause either a flickering or extinguishment of the light. In this way the weaver by moving his hands over a bank of drop wires can readily determine the location of the fallen drop wire, and breakage of the control circuit at the fallen drop wire will not result in objectionable arcing.

With these and other objects in view which appear as the description proceeds, our inven tion resides in the combination and arrangement of parts hereinafter described and set forth.

in the accompanying drawings, wherein a convenient embodiment of our invention is set iorth,

Fig. i is a side elevation of a loom having cur invention applied thereto,

Fig. 2 is an enlarged side elevation of a drop wire with the contact and warp supporting bars shown in section.

Fig. 3 is a diagrammatic View illustrating the manner in which the contact between the drop wire and the contact bar may be interrupted or disturbed for the purpose of determining the location of the broken thread, and

Fig. 4 is a diagrammatic view showing the circuits employed in our invention.

Referring particularly to Fig. 1, the loom frame it has top and bottom shafts ii and i2 and harness frames two of which are indicated at E3. The warp beam M at the back of the loom supplies the warp W which passe upwardly and around a whip roll l5 and then forwardly through the warp stop motion designated generally at A, From the warp stop motion the warp leads forwardly or to the left as viewed in Fig. 1 through the harness frames and then to the fabric 1'.

Operation of the loom is controlled by a ship- Der handle to which is connected a rearwardly extending rod 2| attached as at 22 to an upright lever 23 forming part of a knockofl' mechanism K, Lever 23 is pivoted as at 24 to the mechanism K and has a link 25 pivoted thereto and connected to the core 26 of a solenoid 21. A lever 28 is pivoted on the knockoff mechanism and has an arm 29 which rests on i a cam 30 secured to the bottom shaft l2. An

actuating arm 3| on lever 28 is provided for operation of the link 25.

Under normal running conditions when the solenoid is not energized itscore 28 and the link 25 will be in down position below the path of travel of the actuator arm 3| as lever 28 is oscillated due to rotation of cam 30. The shipper handle 20 will be in the forward running position and lever 23 will be in the full line position shown in Fig. 1. Should the solenoid 21 be energized it core and link 25 will rise and upon the next oscillation of lever 28 in a counterclockwise direction as viewed in Fig. 1 the actuatolarm 3| will engage link 25 and move lever 23 to the dotted line position shown in Fig. 1, thereupon moving rod 2| to the left as viewed in Fig. l to rock the shipper handle from the full line to the dotted line position to effect loom stoppage.

Warp stop motions will ordinarily comprise several banks of drop wires each having its contact bar, but for simplicity of illustration we show but one drop wire and one contact bar. The contact bar 40 is formed of an outer electrode 4| which is suitably supported at the sides of the loom. Within this electrode is a. second or live electrode 42 insulated from the inclosing electrode 4|. The upper part of electrode 4| is round as at 43 and extends above electrode 42. Separator bars 44 support the warp W and are related to the contact bar 40 as indicated in Fig. 2.

The drop wire 45 has a slot 46 in the upper end thereof through which the contact bar 40 passes.

I Ears or projections 41 extend into the slot and the upper part of the drop wire has an arch or bridge 48 extending across the top thereof to connect the two sides of the drop wire on opposite sides of the slot.

Ordinarily the drop wire will be in the raised full line position shown in Fig. 2 with the projections 41 in such position that they cannot electrically connect the electrodes 4| and 42. When the warp thread breaks the drop wire will fall to the dotted line position shown in Fig. 2, whereupon the left hand projection will-engage a rib 49 extending longitudinally of the electrode 4|. This rib causes a camming of the drop wire to the left, thereby moving the right hand projection 41 against the insulated electrode 42. The two electrodes are thus electrically connected and the arch or bridge 48 is located only a short distance above the upper rounded edge 43 of the electrode 4|.

The matter thus far described may be made as set forth in the aforesaid patent to Payne and also another of his Patents No. 1,873,465. In carrying our present invention into effect we provide improved means whereby electric connection of the electrodes 4| and .42 will cause operation of an electronic circuit for the purpose of energizing the solenoid 21. The electric circuit shown in Fig. 4 includes an electronic tube E having plate P, grid G. and cathode C which is bar.

d heated by the filament F. The power lines 50 and 5i are connected respectively to binding posts 52 and 53 which in turn are connected to the primary 54 of a transformer T. The secondary 55 of the transformer supplies power for the filament F,

The cathode C is in the following circuit: post 52, resistance R. cathode C. resistance R, wire 56 back to post 53. The resistances R and R are chosen to give the cathode its usual bias. and electrons emitted from the cathode collect around the grid and cannot escape because of a high resistance R2 which is connected between wire 51 attached to the grid and post 52. Under normal conditions therefore when all the drop wires are raised the grid and resistance R2 cooperate to prevent firing or operation of tube E.

When a drop wire falls to the dotted line position shown in Fig. 2, however, the following signal circuit is closed: post 52, resistance R. cathode C, grid G, wire 41, wire 58. electrode 4|. drop wire 45, electrode 42, wire 59 back to post 52. This signal circuit short circuits. the resistance R2, thereby providing a path of escape for the electrons on the grid. The'potentiai of the latter is therefore altered and current can flow from the cathode C to the plate P.

When the tube is able to pass electric current the following relay circuit is closed: post 52. resistance R, cathode C. through the tube E to plate P, protector resistance R3, relay 60. and wires GI and 56 to post 53. Current flowing in this circuit causes the relay to move its armature 65 into engagement with a contact 66. whereupon the following solenoid circuit is closed: secondary 61 of transformer T. wire 68. armature 55, contact 66, wire 69, solenoid 21, and wire 70 back to the secondary 61. Current flowing in this circuit will energize the solenoid and cause operation of the knockofi mechanism K to stop the loom as already described. The primary H of transformer T may be supplied from the main power lines 50 and 5| by means of wires 12 and 55.

In order that a signal may be given that the Warp stop motion has operated We employ a lamp which will become illuminated whenever the solenoid 21 is energized. As shown herein this lamp L is in parallel with the solenoid, being connected thereto by means of wire 15 and 16, and whenever the solenoid is caused to operate the lamp L will be illuminated to give tbs weaver a signal that loom stoppage has been ceased by a warp fault.

Another feature of the invention relates to the ease with which the location of the broken warp thread may be determined. As shown in Figs. 3 and 4 a drop wire 45 is in down position in full lines and is vertical, the usual position for the drop wire under these conditions. By moving the hand over the bank of drop wire; the fallen drop wire can be tilted to the dotted line position of Figs. 3 and 4, the drop wire moving around the projections 41 as a pivot until the arch 48 engages the top rounded edge 43 of the electrode 4|. During this time contact is preserved between the drop wire and the electrodes of the contact By continued movement of the Weaver's hand the drop wire will move to the dot and dash line position shown in Figs. 3 and 4, the under side of the bridge or arch 48 becoming a pivot for the drop wire. As the drop wire moves to the dot and dash line position the engagement of its proiections 41 with the contact bar 40 will be disturbed or broken. This breaking of contact will ordinarily occur when the right hand projection '5 51 as viewed in Fig. 2 rises above the insulated electrode 4'2.

when this breakage of contact occurs resistance R2 will again control the grid and the latter immediately prevents operation of the tube E, whereupon the relay 6!? is deenergized and its armature 55 moves away from contact 66 and the circuit through the lamp is interrupted. By watching the lamp during this operation the weaver can tell when he has reached the fallen drop wire and can then proceed to repair the broken thread. We find that in this feature of our invention the lamp does not always go out completely when the fallen drop wire is reached by the weaver. It will, however, suiier some diminution of illumination and cause a flickering or" the lamp which will attract the Weaver's attemtion. In any event the illumination of the lamp L is altered and thereby gives Visual signal that the weaver has reached the fallen drop wire.

From the foregoing it will be seen that we have provided a simple electric circuit for an electric warp stop motion wherein the fallen drop wire affects the grid of an electronic tube in such a way that current can flow through the tube for the energization of the relay. It will further be seen that a very small current flows through the fallen drop wire and there is therefore no appreciable heating or burning of the drop wire such as has been common experience in warp stop motions as made heretofore. Furthermore, it will be seen that the resistance R2 which normally cooperates with the grid to prevent operation of the tube, is short-circuited by a fallen drop wire and as a result current can pass through the tube and cause the relay to effect operation of the solenoid and lamp. Also, it will be seen that the potential of the grid can be varied by tilting the fallen drop Wire by a manual operation performed by the weaver, and that the variation in the potential of the grid thus produced causes an alteration in the illumination of the lamp L to indicate the location of the fallen drop wire.

Having thus described our invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and we do not wish to be limited to the details herein disclosed, but what we claim is:

1. In an electric warp stop motion for a loom having an electromagnetic device which when energized eifects loom stopp ge and wherein a. fallen drop wire electrically connects the insulated electrodes of a contact bar, a source of electric power. an electronic tube, electric circuit means lnc1ud= ing the source, tube and device tending normally to energize the latter, a grid forming part of the tube, and a resistance connected to the grid and connected electrically in parallel with said elec trodes and normally cooperating with the grid in such manner as to maintain the grid in such eleC tric condition as to prevent operation of said electric circuit means, the fallen drop wire when electrically connecting said electrodes being effective to short-circuit said resistance, thereby altering the electric condition oi the grid so that the latter cannot prevent operation of said electric circuit means, whereupon said source energizes said device by an electric current flowing through said tube.

2. In an electric warp stop motion for a loom having a solenoid which when energized effects loom stoppage, the loom having a drop wire which when in fallen position due to warp fault electrically connects the insulated electrodes of a contact bar, a source of electric power, an electronic tube, a relay which when energized closes a solenoid contact, electric circuit means including the source tube and relay tending normally to energize the latter, a grid in the tube which by g the normal electric condition thereof prevents said electric circuit means from energizing the relay, electric means including a resistance connected electrically in parallel with said electrodes operative upon electric connection of said electrodes by the fallen drop wire and resultant short-circuting of said resistance to alter the electric condition of said grid, whereupon said electric circuit means energizes said relay, and means operative upon closure of said solenoid contact by the relay to energize said solenoid.

VICTOR F. SEPAVICH.

JOHN C. MANOOG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,873,465 Payne Aug. 23, 1932 1,924,208 Howe et a1. Aug. 29, 1933 2,233,483 Metcalf Mar. 4, 1941 FOREIGN PATENTS Number Country Date 587,951 Germany Nov. 10, 1983 

